Artificial limb having interchangeable leg sections and length adjusting means



m M 5 $4 5 ZMM 4 0 E w MW w W? 5 I fi/WJ Wm. 7/ F 74v; 1 W .1 w 4 W BY 2 E R. C. LINDGREN Aug. 19, 1969 ARTIFICIAL LIME HAVING INTERCHANGEABLE LEG SECTIONS AND LENGTH ADJUSTING MEANS Filed Feb. 15, 1967' United States Patent U.S. Cl. 321 9 Claims ABSTRACT or Inn DISCLOSURE A-n artificial limb which will provide for interchangeability between an artificial foot and peg to enable the user to readily change the load bearing surface of the artificial limb for various activities without removal of the remaining portion of the limb and without disturbing the adjustment of the same. In addition, the improved artificial limb includes means for accurately adjusting the length of the limb for variations in the stump upon which it is mounted due to temperature variations, atrophy and the like. The improvement in the artificial limb resides in the mounting of a threaded shaft through the socket portion and positioning a hemispherically shaped guide plate on the same to give any desired length to the limb and suitable shim means may be inserted between the peripheral edge of the hemispherical plate and the end of the socket portion.

This invention relates to artificial limbs and more particularly to an improvement in an artificial limb to permit ready interchangeability between a peg. and a conventional artificial foot with a simplified adjustment in the length of the artificial limb.

Artificial limbs in the past have varied in size and shape and have included varying methods of adjustment for the same. These prior prosthetic appliances have all been complex in form, particularly in the adjustment, and have not included the versatility of an interchangeability of a peg foot and peg leg. Similarly, adjustment of the same had to be done by an expert and such appliances were subject to damage as well as extensive maintenance.

The present invention is directed to an improved artificial limb which will permit the user to use both a peg leg and an artificial foot with the same basic socket portion and retaining means to retain the limb on the stump of the wearer. It will provide an economical method of interchanging such terminal portions of the limb, as well as provide a simple and economical method of adjustment of the length of the artificial limb. Under certain circumstances, a peg leg is desirable because it permits the wearer greater agility and stability on rough surfaces encountered in various activities, such as hunting, camping, fishing, yard work and many forms of employment. The artificial foot on the other hand is desirable on other occasions for aesthetic purposes. It has not previously been feasible to have such appliances without interchanging the entire unit. This would require the user to own two such limbs and required complete removal of one to change to the other.

From the standpoint of adjustability, it has been recognized that as the age of the stump of the limb increases it tends to atrophy reducing in size and settling into the socket further shortening the overall length of the leg. This usually happens during the first several years of usage and requires the user to get a professional leg adjustment or a change of the appliance. Similarly, changes take place from summer to winter which will also vary the elfective length of the limb by shrinkage of the stump or expansion of the same, requiring regular adjust- "ice ment. If such adjustments are not made, a loss of balance, lower back trouble and alteration of clothing are normally experienced. Thus, it is desirable to have a simplified leg adjustment that the user can make for himself on the limb which will compensate for such conditions.

In the improved artificial limb, a threaded shaft is secured to the socket portion of the limb and varying types of retaining means, such as corsets or the like may be employed to retain the socket on the stump. The threaded Shaft has mounted thereon a curved or hemispherically shaped plate which will be threaded on the shaft and will support a form member also threaded on the shaft below the plate which will position the peg foot or the artificial foot from a length standpoint. Suitable shims may be employed between the end of the socket portion and the curved plate to vary the length of the limb for minor adjustments. The form member will normally be similar to or take the place of the actual peg leg and the actual contact engaging portion of the peg will thread into the same with a second shaft so as to be readily removable therefrom. When an artificial foot is used, the foot is similarly assembled on the form member through a threaded shaft and a leg form is positioned over the form member to engage the artificial foot and bear against the curved plate of the upper extremity to provide a conventional leg form. In the installation of the leg, the initial settings do not have to be made with such accuracy since the foot or peg portion may be adjusted by positioning the curved plate on the shaft for desired length. Thus, the user may go from an artificial foot to a peg leg for varying types of activity while still retaining with the limb the desired artificial foot and leg for aesthetic purposes under certain conditions.

Therefore, it is an object of this invention to provide an improved artificial limb.

Another object of this invention is to provide an artificial limb which permits interchangeability between a peg leg and an artificial foot.

A further object of this invention is to provide in an artificial limb, a simplified means for adjusting the length of the same.

A still further object of this invention is to provide an artificial limb in which a peg foot or an artificial foot may be readily interchanged by a user for varying types of activity without altering the overall length of the limb or requiring further adjustment of the same.

These and other objects of this invention will become apparent from a reading of the attached description together with the drawings wherein:

FIGURE 1 is an elevation view of the improved artificial limb with a peg leg extremity;

FIGURE 2 is an elevation view of the improved artificial limb with an artificial foot extremity;

FIGURE 3 is a sectional view of the improved artificial limb showing the connection to the socket portion thereof;

FIGURE 4 is a sectional view of the improved artificial limb showing the peg leg extremity;

FIGURE 5 is a sectional view of the improved artificial limb with the artificial foot extremity.

The improved artificial limb utilizes the conventional socket portion of an artificial limb, indicated generally at 10, with the exception that it includes provision for mounting a shaft 20 at the closed extremity of the same. This socket portion may be made out of any suitable material, such as, fiberglass, plastic or wood and will normally include a liner 15 which will fit around and support the stump of a limb. Attached to the socket portion is a retaining member, indicated at 25 which may be of the corset or strap type and made out of a suitable fabric to be laced or buckled together to secure the artificial limb to the upper portion of the stump. In the drawing, FIG

URES 1 and 2 show alternate versions of the retaining member. This portion of the limb may vary in form and shape and its detail forms no part of the invention. In FIGURE 1, the improved artificial limb is shown with a peg leg attached to the socket portion, as indicated at 30, and a ground engaging cap or foot member 35 attached thereto. In FIGURE 2, the artificial limb has an artificial foot 36 and a leg form 38 attached to the socket portion as its ground engaging portion or member, as will be hereinafter defined.

The sectional view in FIGURE 3 discloses the closed extremity of the socket portion in section to show the attachment of the shaft 20 thereto which supports and connects the various extremities, such as the peg leg or the artificial leg and foot. Thus, in FIGURE 3, the socket portion is shown with parts broken away as having an aperture 40 at the closed extremity of the same through which the shaft extends. The aperture 40 is centrally located in the closed extremity of the socket portion and the shaft 20, which is threaded along its entire extent, is secured thereto by lock nuts 42 and washers 44 positioned on either side of the aperture 40. Also, included in the aperture is a spacer member 45 which together with the lock nuts 42 are threaded onto the shaft to securely position the shaft in the closed extremity of the socket portion 10. Mounted on shaft 20 is a curved plate or hemispherically shaped plate 50' which has a threaded aperture 52 centrally located therein to permit the plate to be threaded on the shaft 20 in varying positions thereon. Positioned between the peripheral edge of the curved or hemispherically shaped plate and the end of the socket portion are a plurality of shim type washers 53 of a predetermined thickness which act as a shim or adjusting means to fill the space between the plate 50 and the end of the socket portion during adjustment, as will be hereinafter identified.

The peg leg extremity for the artificial limb is shown in section in FIGURE 4 to disclose the relationship of parts and to indicate the installation and interchange ability of the same. The socket portion and any suitable retainer (not shown) is utilized with the shaft 20 secured therein, as indicated in FIGURE 3. The curved hemispherically shaped plate 50 threads onto the threaded shaft 20 secured in the socket portion and is adjusted on the shaft to provide a given reference point or measurement for the length of the limb. As indicated in FIG- URE 3, suitable shims 53 may be placed between the ends of the plate 50 and the socket portion 10 if the socket portion is adjusted to leave a gap therebetween. A peg form or form member is mounted on the shaft 20, this form having a threaded aperture 58 therethrough with a curved upper extremity, as indicated at 60, (16-, signed to fit flush against and conform to the exposed surface of the hemispherically shaped plate 50. The opposite extremity of the form member 30 is fiat, as at 62, and the shaft 20 extends only through part of the tapped aperture 58 in the form member. The foot or ground engaging portion or member of the peg leg includes an outer cup member 65, normally made of rubber, with a metal insert 66 therein having an outer peripheral surface 67 designed to grip to the cup member or rubber extremity 65. It includes an internal tapped aperture 70 mounting a second shaft 72 having the same threads as the shaft 20' and the tapped aperture 58 in the form member. The shaft 72 will thread into the form member at the lower extremity or fiat extremity of the same so that the surface of the insert 66 will engage the same. This will provide an assembly of a peg leg whose length adjustment will be varied by positioning the plate 50 on the shaft 20. A set screw 69 threaded through the form member 30 and against the shaft 20 will hold the peg leg securely mounted on the shaft 20. Under certain conditions, the cup member 65 with its shaft 72 may be permanently secured to the form member 30 through means, such as by gluing in a custom installation. To interchange the extremities of the artificial limb, or remove 4. the peg leg, the set screw will first be released from its locking position with a shaft 20 and thereafter the entire assembly may be removed by turning the form member 30 off of the shaft 20. Where the extremity parts are not permanently connected together, the cup member with its shaft may be removed from the form member by threading the shaft 72 out of the same and thereafter removing the form member 30 by turning it off of the shaft to leave the shaft 20 exposed for an installation of a different leg form.

As will be seen in FIGURE 5, the leg form includes an inner form member 75 similar to the form member 30 with a tapped aperture 76 therein which is similar to aperture 58, and which will mount or thread on the shaft 20. Its upper surface 'is curved, as at 80, and its lower surface is flush or flat at 82 with this form member being threaded onto the shaft until the curved surface 80 engages the plate member 50. The outer surface of the form member 75 is roughened and may include threads, such as is indicated at 85, for the purpose of positioning the leg form 38 thereon. The artificial foot 36 is a conventional member which may vary in form and will mount a secondary shaft 89 suitably secured in the foot by means of a lock nut 90 and washer 91 with a metal plate 92 on the upper surface of the same through which the shaft 89 extends. The secondary shaft 89 has the same threading as the form member 75 and the shaft 20 and will thread into the aperture 76 of the form member 75 until the foot is positioned with the metal plate 92 hearing against the extremity 82 of the form member. Before the foot member 36 is inserted or attached to the form member 75, the leg form 38 is positioned on the form member 75. This leg form will represent a continuation of the leg and has a curved upper surface 95 designed to conform with the curved hemispherically shaped plate 50 and a flat or flush surface at the outer extremity, as indicated in 96, so as to bear against the top of the foot 36. The aperture in the leg form is threaded or roughened, as indicated at 98 to permit the leg form 38 to be threaded onto the form member 75 of the outer periphery of the same to secure the leg form on the form member 75. Thereafter the foot 36 is assembled thereon. A suitable set screw 99 threaded through a tapped aperture in the leg form 38 and form member 75 to bear against the shaft 20 will lock the leg form in position on the shaft 20. As in the case of the peg leg, the leg form after initial custom installation may be assembled so that the leg form 38, the form member 75, the foot 36 together with its mounting shaft 89 may become an integral unit by suitably securing the parts in assembled relationship and gluing or otherwise causing the same to adhere to one another. Removal of the leg under these conditions may 7 be effected by merely threading the entire assembled foot assembly off of the threaded shaft 28 as in the case of the peg leg. If the parts are individual, assembly and dis assembly will be elfected by removing the foot 36 by removing its shaft 89 from the form member 75 and thereafter removing the leg form 38 and the form member from one another and the shaft 20.

In this improved artificial limb, the initial installation will be made by adjusting the length of the shaft 20 in the installation of the same in the socket portion of the limb 10 by a professionally qualified person. It will be adjusted in length to permit the plate 50 to be mounted thereon and define a reference point for the peg leg form or the artificial leg and foot form to give the same rcsultant overall length with the artificial limb for the wearer. As temperature variation affects the size and shapeof the human leg stump or as atrophy varies its form to decrease the length of the leg or stump, adjustment of the limb may be made by the user simply by adjusting the position of the plate 50 on the shaft 20. The initial installation will preferably provide for a number of shims between the plate 50 and the end of the socket portion 10 so that they may be added to or removed to fill the gap between the curved plate and the end of the socket portion and provide a fixed adjustment preventing the curved plate from moving as the length of the limb is altered. Once the initial installation is made, such adjustments may be effected by the user. This will keep the leg lengths the same permitting a correct balance for the user and eliminate the health hazards which result from one leg being shorter than the other. The substitution for the artificial foot and leg with a peg leg will normally be made for specialized activity wherein appearance is not an important factor. The artificial foot may be exchanged for the peg leg by unscrewing the same from the shaft as indicated above with the peg leg form being installed as a single unit or as in individual components. The artificial leg 38 and foot 36 together with the form members 30 and 75 may vary in the type of material used in manufacture of the same. The supporting plate or hemispherically shaped plate member 50 is perferably made of a stainless steel as are the shafts and lock nuts to resist corrosion.

In considering this invention, it should be remembered that the present disclosure is intended to be illustrative only and variation may be made in the shape or parts and materials employed without departing from the scope of the invention. Therefore, I wish to be limited only by the appended claims.

What is claimed:

1. An artificial limb having a socket portion adapted to fit over and cover the stump end of a human limb with a retaining means secured to the open end of the socket portion and adapted to extend back over the human limb to secure the socket portion thereon, the improvement residing in a shaft position through the closed end of the socket portion concentric therewith and extending out of said socket portion and away from said retaining means, .a curved plate member having an aperture centrally located therein and with peripheral dimensions symmetrical with the closed end of the socket portion, said curved plate member being positioned over said shaft and having means therein adapted to cooperate with means on said shaft to adjustably position the curved plate on the shaft relative to the end of the socket portion, a threaded surface on said shaft beyond said curved plate and extending over the extent of the same, a form memher having a threaded aperture therethrough positioned on the threaded extremity of the shaft and abutting the curved plate, and a ground engaging contact member included with the form member, said curved plate being adjustably positioned on said shaft to adjust the length of the artificial limb and the form member being interchangeable with varying forms of the ground engaging contact member to be mounted on said shaft.

2. The artificial limb of claim 1 in which the curved plate member is hemispherically shaped in form and the shaft connected to the socket portion is threaded along its entire extent with the hemispherically shaped plate having a threaded aperture therein such that the plate may be threaded into the shaft to any desired position thereon.

3. The artificial limb of claim 2 and including a plurality of shims positioned between the peripheral edge of the hemispherically shaped plate and the closed end of the socket portion for spacing purposes.

4. The artificial limb of claim 3 in which the form member has a curved extremity that to conform with the curved surface of the hemispherically shaped plate and a flat surface of the opposite extremity to be engaged by the ground engaging contact member.

5. The artificial limb of claim 1 in which the ground engaging contact member includes a shaft threaded into the threaded aperture of the form member at the extremity remote from the curved plate and adapted to bear against the extremity of the form member with said threaded aperture on the form member being adapted to receive threaded shafts from varying forms of ground engaging contact members to provide interchangeability in the type of ground engaging contact member for the artificial limb without further adjustment in the length of the artificial limb.

6. The artificial limb of claim 5 in which the ground engaging contact member is a peg member with a shaft secured thereto and threaded into the threaded aperture of the form member.

7. The artificial limb of claim 5 in which the ground engaging contact member is an artificial foot having a shaft means secured therein and extending beyond the upper surface thereof and being threaded into the threaded aperture in the form member with a leg form positioned over the form member and having an internal surface passage therein mounted on the outer peripheral surface of the form member and a curved extremity adapted to fit around and conform to the surface of the hemispherically shaped plate and a flat surface at the other extremity adapted to fit against the top of the artificial foot.

8. The artificial limb of claim 5 in which the threaded shaft secured to the socket portion extends into the form member over a portion of its internal threaded aperture and in which the threaded shaft in the ground engaging contact member threads into the opposite extremity of the threaded aperture of the form member being spaced from the first named shaft in the secured position.

9. The artificial limb of claim 8 in which the ground engaging member includes means for mounting the shaft in the ground engaging member and a surface on the ground engaging member adapted to abut and be flush with the extremity of the form member into which the shaft of the ground engaging member is threaded for support thereon.

References Cited UNITED STATES PATENTS 129,340 7/1872 Hawkins 3-21 XR 623,741 4/1899 Riebel 32O 1,032,074 7/1912 Marks 3-16 XR 1,144,681 6/1915 Apgar 3-17 XR 1,340,239 5/1920 Nelson 3-16 2,080,003 5/1937 Blevens 316 3,400,408 9/1968 Garcia 3-21 XR FOREIGN PATENTS 978,586 12/ 1964 Great Britain.

RICHARD A. GAUDET, Primary Examiner RONALD L. FRINKS, Assistant Examiner us. 01. X.R. 3-16; 2s7 s2 

